/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package com.sun.org.apache.xerces.internal.util;

import com.sun.org.apache.xerces.internal.xni.XMLString;

/**
 * XMLString is a structure used to pass character arrays. However,
 * XMLStringBuffer is a buffer in which characters can be appended
 * and extends XMLString so that it can be passed to methods
 * expecting an XMLString object. This is a safe operation because
 * it is assumed that any callee will <strong>not</strong> modify
 * the contents of the XMLString structure.
 * <p>
 * The contents of the string are managed by the string buffer. As
 * characters are appended, the string buffer will grow as needed.
 * <p>
 * <strong>Note:</strong> Never set the <code>ch</code>,
 * <code>offset</code>, and <code>length</code> fields directly.
 * These fields are managed by the string buffer. In order to reset
 * the buffer, call <code>clear()</code>.
 *
 * @author Andy Clark, IBM
 * @author Eric Ye, IBM
 */
public class XMLStringBuffer
    extends XMLString {

  //
  // Constants
  //


  /**
   * Default buffer size (32).
   */
  public static final int DEFAULT_SIZE = 32;

  //
  // Data
  //

  //
  // Constructors
  //

  /**
   *
   */
  public XMLStringBuffer() {
    this(DEFAULT_SIZE);
  } // <init>()

  /**
   *
   *
   * @param size
   */
  public XMLStringBuffer(int size) {
    ch = new char[size];
  } // <init>(int)

  /**
   * Constructs a string buffer from a char.
   */
  public XMLStringBuffer(char c) {
    this(1);
    append(c);
  } // <init>(char)

  /**
   * Constructs a string buffer from a String.
   */
  public XMLStringBuffer(String s) {
    this(s.length());
    append(s);
  } // <init>(String)

  /**
   * Constructs a string buffer from the specified character array.
   */
  public XMLStringBuffer(char[] ch, int offset, int length) {
    this(length);
    append(ch, offset, length);
  } // <init>(char[],int,int)

  /**
   * Constructs a string buffer from the specified XMLString.
   */
  public XMLStringBuffer(XMLString s) {
    this(s.length);
    append(s);
  } // <init>(XMLString)

  //
  // Public methods
  //

  /**
   * Clears the string buffer.
   */
  public void clear() {
    offset = 0;
    length = 0;
  }

  /**
   * append
   */
  public void append(char c) {
    if (this.length + 1 > this.ch.length) {
      int newLength = this.ch.length * 2;
      if (newLength < this.ch.length + DEFAULT_SIZE) {
        newLength = this.ch.length + DEFAULT_SIZE;
      }
      char[] tmp = new char[newLength];
      System.arraycopy(this.ch, 0, tmp, 0, this.length);
      this.ch = tmp;
    }
    this.ch[this.length] = c;
    this.length++;
  } // append(char)

  /**
   * append
   */
  public void append(String s) {
    int length = s.length();
    if (this.length + length > this.ch.length) {
      int newLength = this.ch.length * 2;
      if (newLength < this.ch.length + length + DEFAULT_SIZE) {
        newLength = this.ch.length + length + DEFAULT_SIZE;
      }

      char[] newch = new char[newLength];
      System.arraycopy(this.ch, 0, newch, 0, this.length);
      this.ch = newch;
    }
    s.getChars(0, length, this.ch, this.length);
    this.length += length;
  } // append(String)

  /**
   * append
   */
  public void append(char[] ch, int offset, int length) {
    if (this.length + length > this.ch.length) {
      int newLength = this.ch.length * 2;
      if (newLength < this.ch.length + length + DEFAULT_SIZE) {
        newLength = this.ch.length + length + DEFAULT_SIZE;
      }
      char[] newch = new char[newLength];
      System.arraycopy(this.ch, 0, newch, 0, this.length);
      this.ch = newch;
    }
    //making the code more robust as it would handle null or 0 length data,
    //add the data only when it contains some thing
    if (ch != null && length > 0) {
      System.arraycopy(ch, offset, this.ch, this.length, length);
      this.length += length;
    }
  } // append(char[],int,int)

  /**
   * append
   */
  public void append(XMLString s) {
    append(s.ch, s.offset, s.length);
  } // append(XMLString)


} // class XMLStringBuffer
